Introduction

Obesity is not merely about weight gain—it may also increase the risk of developing autoimmune diseases. In this article, based on the latest scientific evidence, we explore the deep connection between obesity and autoimmune diseases, the mechanisms behind their onset, and key points for prevention and treatment.

1. Does Obesity Trigger Autoimmune Diseases?

Recent studies have revealed that obesity increases the risk of many autoimmune diseases, such as rheumatoid arthritis, type 1 diabetes, and multiple sclerosis (MS). Furthermore, a genetic research method called Mendelian randomization (MR) (Li X, Zhu J, Zhao W, et al.) has provided strong evidence that obesity can be a direct cause of autoimmune diseases.

• Rheumatoid Arthritis: Obese women have about a 1.3 times higher risk of developing rheumatoid arthritis compared to women with normal weight.
• Type 1 Diabetes: Childhood obesity more than doubles the risk of type 1 diabetes.
• Multiple Sclerosis: Every 1-point increase in BMI raises the risk of developing multiple sclerosis by about 1.4 times.

Other research also suggests that obesity is linked to various autoimmune diseases, including psoriasis and autoimmune thyroiditis.

2. Mechanisms Linking Obesity and Autoimmune Diseases

Chronic Inflammation

In obesity, adipose tissue releases excessive inflammatory cytokines (IL-6, TNF-α, IL-1β), triggering chronic inflammation. This lays the foundation for the development of autoimmune diseases.

Imbalance of Cytokines (Th17/Treg Disruption)

Obesity increases leptin levels, which promote the proliferation of Th17 cells (inflammatory) while weakening the function of regulatory T cells (Treg), which are anti-inflammatory. A decrease in adiponectin further reduces anti-inflammatory effects, making autoimmune reactions more likely.

Disruption of the Gut Microbiome

Obesity-induced changes in gut microbiota increase intestinal permeability, allowing endotoxins to leak into the bloodstream and overstimulate the immune system (metabolic endotoxemia). This is another factor that can trigger autoimmune diseases.

3. Approaches for Prevention and Treatment

• Proper Weight Management: Weight reduction can lower disease activity in conditions such as rheumatoid arthritis and psoriasis.
• Anti-inflammatory Foods: A Mediterranean-style diet and foods rich in omega-3 fatty acids help suppress inflammation and maintain immune balance.
• Regular Exercise: Consistent aerobic exercise and strength training can reduce chronic inflammation and improve gut health.
• Utilizing Obesity Treatments: In addition to dietary and exercise therapies, the use of anti-obesity medications (e.g., GLP-1 analogs) or bariatric surgery, when necessary, can support effective autoimmune disease management.

4. Summary

The chronic inflammation and immune dysregulation caused by obesity can increase the risk of various autoimmune diseases. However, these risks can be significantly reduced through proper weight management, an anti-inflammatory diet, and consistent exercise habits. Collaboration with specialists and a comprehensive approach to managing both obesity and autoimmune diseases are crucial.

References

1. Li X, Zhu J, Zhao W, et al. (2023). “The causal effect of obesity on the risk of 15 autoimmune diseases: A Mendelian randomization study.” Obes Facts.
2. Gardner et al. (2018). “Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults.” JAMA.
3. Johnston et al. (2014). “Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults.” JAMA.
4. Estruch et al. (2013). “Primary Prevention of Cardiovascular Disease with a Mediterranean Diet.” NEJM.